Inertia Newton’s first law of motion Relationship between mass and inertia

tendency of the object to remain at rest or, if moving, to continue its uniform motion in a straight line Object remain at rest or in uniform motion unless it’s acted upon by external force The larger the mass, the larger its inertia

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Situation related to inertia

Momentum Principle of conservation of momentum Elastic collision

Momentum, p = mass, m x velocity, v

SI unit= kg m s-1

In the absence of an external force, the total momentum of a system remains unchanged.

Gravitational force Free fall Weight Forces in equilibrium Newton’s Third law of motion Work Kinetic energy Potential energy Principle of conservation of energy Power Hooke’s law

- Shatter-proof windscreen - Safety seat belt - Padded dashboard Pulled by the force of gravity – tends to pull everything towards the earth’s centre Object is fall freely when it’s falling under the gravitational force only with acceleration due to gravitational force, g = 10.0 N kg-1 Gravitational force acting on the object. W=mg SI unit= Newton, N When an object is in equilibrium, the resultant force is zero. The object will either be at rest or move with constant velocity For every action there is an equal an opposite reaction Work, W = Force, F X Displacement, s SI unit= Joule, J K.E = ½ mv 2 SI unit= Joule, J P.E = mgh SI unit= Joule, J Energy cannot be created or destroyed but can be changed from one form to another form. Power, P =

workdone timetaken

=

W t

SI unit= Watt, W

Force constant Elastic limit Graph

the extension of a spring is directly proportional to the applied force provided that the elastic limit is not exceeded F = kx, k = Force constant of the spring k = F SI unit N m-1, N cm -1 or N mm-1 x maximum force that can be applied to spring such that the spring will return to its original length when the force released F/N Elastic limit

Exercises
1. Diagram show two watermelons fall off the table and drop on to the surface A and surface B respectively

Diagram 1 (a)

Diagram 1 (b)

a) What is mean by impulse ? …………………………………………………………………………………………………………………………………………………………. (1 mark) b) With reference to Diagram 1(a) and 1(b) i) Compare the force on the watermelons that strikes on surface A and surface B …………………………………………………………………………………………………………………………………………………………. (1 mark) ii) Compare the time of impact of the watermelons on surface A and surface B …………………………………………………………………………………………………………………………………………………………. (1 mark) iii) State the relationship between the force produced in a collision and the time of impact …………………………………………………………………………………………………………………………………………………………. (1 mark) c) Suggest a suitable material for surface B …………………………………………………………………………………………………………………………………………………………. (1 mark)

d) Explain how the driver is able to avoid serious injuries when the car stopped suddenly …………………………………………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………………………………………. (2 mark)

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2.

a) i)

ii)

iii)

b)

When a load is attached to the spring What happen to the length of the spring ? ………………………………………………………………………………………………………………………………………………….. (1 mark) What is the energy stored in the spring ? ………………………………………………………………………………………………………………………………………………….. (1 mark) If the number of load is increased, what will happen to the energy in 2(a)(ii) ? ………………………………………………………………………………………………………………………………………………….. (1 mark) The initial length of a spring is 15 cm. When a load with mass 300 g is attached to the spring, the length of the spring is 21 cm. What is the length of the spring if a load with mass 500 g is attached to the spring?

(3 mark)

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3. Diagram 3.1 and Diagram 3.2 show a student throwing a javelin using different throwing techniques. The forces used by the student are the same. The angles of projection are different.

Javelin

A Diagram 3.1

B

A Diagram 3.2
(a) (i) Observe Diagram 3.1 and Diagram 3.2.

B

Compare the distance traveled by the javelin from A to B. ………………………………………………………………………………………………………………………………………………….. (1 mark) (ii) What happens to the distance of the javelin when the angle of projection is less than the angle of projection shown in Diagram 3.2? ………………………………………………………………………………………………………………………………………………….. (1 mark) (b) State the shape of the javelin so that it moves with minimum resistance through air ………………………………………………………………………………………………………………………………………………….. (1 mark) (c) The force acting on the javelin is 10 N and the throwing distance 70 m. Calculate the work done by the student in Diagram 3.2.

[2 marks]

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(d) (i) State the changes of energy experienced by the javelin from A to B for techniques. ………………………………………………………………………………………………………………………………………………….. (1 mark) (ii) State the energy produced when the javelin touches the ground. ………………………………………………………………………………………………………………………………………………….. (1 mark)

Notes
Definition of Pressure Formula Pressure is force per unit area P= F A Where P = Pressure F = Force A = Area -2 Nm / Pascal (Pa) - The higher the force, the higher the pressure (where area is constant) - The smaller the area, the higher the pressure (where force is constant)

Characteristics of pressure in liquid Relationship between pressure in liquid, depth and density of liquid

pressure in a liquid is the product of depth, density and gravitational acceleration Pressure in liquid = ρgh where ρ = density of the liquid g = gravitational force h = depth - acts equally in all directions - not depends on surface area and shape of the container - The deeper the depth, the higher the pressure in liquid - The higher the density of the liquid, the higher the pressure in liquid

when an object is wholly or partially immersed in a fluid, it experiences a buoyant force equal to the weight of the fluid displaced Upward force resulting from an object being wholly or partially immersed in a fluid

You are required to determine the most suitable balloon which can be used for safe recreation. Study the specifications of all the four balloons from the following aspects: Anda dikehendaki untuk menentukan belon yang paling sesuai untuk digunakan secara selamat untuk rekreasi. Kaji spesifikasi keempat-empat belon berdasarkan aspek-aspek berikut: - the balloon envelope Karung belon

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- the size of the balloon saiz belon - the number of burner used bilangan pemanas yang digunakan - the type of basket used to carry the passenger. jenis bakul yang digunakan untuk mengangkut penumpang. Explain the suitability of the aspects. Justify your choice. Terangkan kesesuian aspek-aspek itu. Beri sebab bagi pilihan anda. [ 10 marks ]
d) A hot air balloon is adhered to the ground. The balloon contains 1200 m3 of hot air of

Arrangement of apparatus. Susunan radas. The procedures of the experiment which include the method of controlling the manipulated variable and the method of measuring the responding variable. Prosedur eksperimen termasuk kaedah mengawal pembolehubah dimanipulasi dan kaedah mengukur pembolehubah bergerak balas) The way you would tabulate the data. Cara anda menjadualkan data The way you would analyse the data. Cara anda menganalisis data. [10 marks]

Liquid cannot be compressed easily Bernoulli’s principle X Gas flow out the nozzle at highest speed - Air from outside is pushed into the hole - complete combustion occur there - insecticide sprayer Upward force resulting from an object being wholly or partially immersed in a fluid - when the ballast tank is filled with water - the buoyant force is smaller than the weight of the submarine. It will sink / submerges - when the ballast tank is filled with air / when the water pumps out - the buoyant force is larger than the weight of the submarine and it will float envelopes – construct from nylon - Lightweight material - Reduce the total weight of the balloon. - Strong, can withstand the strong winds which could easily wreck the balloon. - Displace more volume of air - Weight of air displaced is greater - To create sufficient buoyant force. Lift up the balloon higher.

1 1 1 1

c

balloon should be large size

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use two burners the basket must be made of rattan

- To warm up the air in the balloon quickly - To keep the balloon rising - Light and flexible/safe material - Prolong the collision time between basket and ground / reduce impulsive force

i) The measuring cylinder is completely filled with water. ii) The thistle funnel is connected to the manometer with a rubber tube. iii) The thistle funnel is lowered with the water to a depth y = 10.0m iv) The manometer reading, h is measured by using the ruler v) Step 3 is repeated with values of depth y = 20.0m, 30.0 cm, 40.0 cm and 50.0 cm.

Heating and cooling curves Notes: Heat is a form of energy. In matter, heat is stored in the form of random kinetic energy and potential energy of the molecules (also called internal energy). Temperature is a measure of the degree of hotness. Thermal equilibrium between two bodies means that there is no net heat flow between them. At thermal equilibrium, both bodies have the same temperature. Thermometric property is the physical property of a substance which varies linearly with temperature. Celsius scale of temperature: The temperature,  is defined as

Example: What is the temperature reading of the thermometer shown below?
L  = 20 cm

Temperature,  
0oC L0 = 5 cm L 100 = 25 cm 100 oC

L  L0  100 L100  L0
20  5  100 25  5



 = 75oC

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Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

Heat capacity of a body is the amount of heat required to raise the temperature of the body by 1oC. heat heat capacity  change of temperature

C

Q 

The S.I. units of heat capacity are J oC-1 or J K-1

Specific heat capacity of a substance is the amount of heat required to raise the temperature of 1 kg of the substance by 1oC. heat specific heat capacity  mass  change of temperature

c

Q m

The S.I. units of heat capacity are J kg-1 oC-1 or J kg-1 K-1

Latent heat is the heat absorbed or released at constant temperature during a change of phase of a substance. Specific latent heat of fusion is the quantity of heat required to change 1 kg of a substance from solid state to liquid state without change of temperature.

specific latent heat  Q m

heat to change substance from solid to liquid mass of the substance
The S.I. units of specific latent heat of fusion is J kg-1

L

Specific latent heat of vaporisation is the quantity of heat required to change 1 kg of a substance from liquid state to gaseous state without change of temperature.
specific latent heat  Q m heat to change substance from liquid to gas mass of the substance

EXERCISE 1: PART I State whether the following statements are true or false. a) Heat is a form of energy. (true / false) b) A body at 0oC does not contain heat. (true / false) c) Heat is stored in a body as internal energy. (true / false) 4

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Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

d) Heat flows both from a hot body to a cold body as well as from a cold body to a hot body. (true / false) e) When thermal equilibrium between two bodies is achieved, the flow of heat stops. (true / false) f) Two bodies in thermal equilibrium must have the same temperature. (true / false) g) The Celsius scale of temperature consists of 100 fixed points. (true / false) h) The upper fixed point and the lower fixed point must be calibrated at atmospheric pressure. (true / false) i) To calibrate the lower fixed point of a thermometer, it is placed in melting ice. (true / false) j) To calibrate the upper fixed point of a thermometer, it is place in boiling water. (true / false) PART II State whether the following statements are true or false. a) The amount of heat stored in a body is directly proportional to is mass. (true / false) b) The amount of heat stored in a body is independent of the type of material it’s made of. (true / false) c) When the temperature of a body decreases, heat is released. (true / false) d) If the specific heat capacity of a substance is high, it means it is easily cooled. (true / false) e) When a solid is melting, its temperature remains the same even though heating continues. (true / false) f) During the melting process, heat absorbed is used to increase the separation between molecules. (true / false) g) When steam condenses to water at a fixed temperature of 100oC, no heat is absorbed or released because there is no change of temperature. (true / false) h) Sea and land breezes are caused by the differences between the specific latent heat of sea water and the specific latent heat of land material. (true / false) i) To be scalded by steam is worse than to be scalded by boiling water even though their temperatures are the same. (true / false) j) An accurate thermometer must have a large heat capacity. (true / false) k) The thermometric property used in the mercury in glass thermometer is length. (true / false) l) A frying pan should be made of material with high specific heat capacity. (true / false) m) A thermometer must be made from materials which are poor heat conductors. (true / false) PART III State whether the following statements are true or false. a) Boyle’s law is always correct even if the temperature of the gas varies. (true / false) b) According to Boyle’s law, when pressure is doubled, the volume of gas is halved. (true / false) c) Gas pressure exerted on the walls of a container is caused by the bombardments of the gas molecules on the walls. (true / false) d) When temperature increases, the kinetic energy of gas molecules increases. (true / false) e) According to Charles’ law, the pressure of a gas increases when temperature increases. (true / false) 5

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Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

f) According to Pressure law, the pressure of a gas is directly proportional to its temperature measured in degree Celsius. (true / false) g) The pressure of air in a car tyre will increase after the car has traveled a long distance. (true / false) EXERCISE 2: PART 1: 1) The S.I. unit of heat energy is A. Watt B. Joule C. Ampere 2) Heat is stored in a body as A. potential energy only energy

D. Coulomb

B. kinetic energy only

C. potential and kinetic

3) Two bodies P and Q are in thermal contact. The temperature of P is higher. A. Heat flows only from P to Q B. Heat flows only from Q to P C. Rate of heat flow from P to Q is greater than that from Q to P 4) Thermal equilibrium between two bodies is reached when A. both bodies have the same amount of internal energy B. the flow of heat between the two bodies stops C. both bodies looses heat to the surrounding at the same rate D. the rate of transfer of heat from each body to the other is the same 5) The sensitivity of a mercury in glass thermometer can be increased by A. using thicker glass to make the thermometer B. using a larger bulb for the thermometer C. using a larger bore for the capillary tube 6) What is the thermometer reading in the diagram?

40 o

30o mercur A. 36oC B. 37oC C. 38oC

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Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

7)
L  = 20 cm 0 oC L0 = 5 cm L 100 = 30 cm 100 oC

Based on the values shown in the diagram above, what is the temperature reading of the thermometer? A. 30oC B. 40oC C. 50oC D. 60oC

what is the temperature reading of the thermometer? A. 30oC B. 40oC C. 50oC D. 60oC 9) When calibrating the lower fixed point for a mercury thermometer, the thermometer must be placed in A. B. C. D. solid ice at atmospheric pressure solid ice at any pressure melting ice at atmospheric pressure melting ice at any pressure

10) Which of the following is not the reason why mercury is suitable for making a laboratory thermometer? A. B. C. D. E. high density low freezing point high boiling point good conductor of heat does not stick to glass

0.01 kg of substance Q (solid) is heated at a constant rate. Its temperature rises as shown in the graph. If the specific latent heat of substance Q is 1200 J kg-1 oC -1, how much heat is required to raise its temperature from 0oC to its melting point? A. 120 J B. 960 J C. 8000 J D. 12000 J

19) Which of the following graphs is true of a gas which obeys Boyle’s law? A. P B. P C. PV

0

1 V

0

1 V

0

1 V

20) Which of the following graphs is true of a gas which obeys Charles’ law? A. PV B. V C. V

0

T

0

T

0

1 T

21) Heat is supplied at the same rate to 100g of paraffin and to 100g of water in similar containers. Why does the temperature of paraffin rises more quickly? A. B. C. D. The paraffin has a larger specific heat capacity than water The paraffin has a smaller specific heat capacity than water Paraffin is less dense than water Paraffin is more dense than water

22) A new liquid is tested to decide whether it is suitable to be used in a liquid-in-glass thermometer. It is found that the liquid does not expand uniformly with change of temperature. What will be the effect of this on the scale of the thermometer? A. B. C. D. It has a short range It is not linear The markings are too close together The markings are too far apart

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9

Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

23) Four mercury-in-glass thermometers are made with different dimensions. Length

Final condition (after copper is dropped into water) Based on the information given, what is the equilibrium temperature, ? (Assume no loss of heat to the surroundings). A. 32.7 oC B. 36.2 oC C. 40.5 oC D. 65.4 oC

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11

Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

EXERCISE 2: PART II: 1. A non-insulated alluminium block is heated at a constant rate using a low power immersion heater. The result is shown by the temperature against time graph. Electric current thermometer Temperature,  / oC

Low power Heater 60 45 Non insulated alluminium block 30 A

B

0 0

Time, t / minute

a)

What is the room temperature?

……………………………………………………………………………………………….. [1 mark] b) Explain why the temperature becomes constant at 60 oC even though heat is still supplied to the block? ………………………………………………………………………………………………… ………………………………………………………………………………………………… [2 marks] c) What does the gradient of the graph represent? ………………………………………………………………………………………………… [1 mark] d) Compare the rate of heat loss to the surroundings at point A and point B. ………………………………………………………………………………………………… [1 mark] 12

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Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

e) The specific heat capacity of alluminium is 900 J kg-1 oC -1 and the mass of the alluminium block is 1 kg. How much heat is required to raise the temperature of the block from 30oC to 60 oC if there is no heat loss? [2 marks]

2. Solid naphthalene is placed in a test tube and then heated as shown in the diagram. The graph shows how the temperature of the naphthalene changes with time.

thermometer stirrer Temperature / oC Test tube beaker 90 80 water Naphthalene 30 0 Bunsen burner a. What is the use of the stirrer? ………………………………………………………………………………………………… [1 mark] b. State the melting point of naphthalene. ………………………………………………………………………………………………… [1 mark] c. (i) What is happening to the state of the naphthalene between time 200 s and 600 s? ………………………………………………………………………………………………… [1 mark] time / s

0

200

600

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13

Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

c. (ii) Explain why the temperature of the naphthalene is constant even though heat is still supplied ………………………………………………………………………………………………… ………………………………………………………………………………………………… [2 marks] d. Why does the temperature rise again after 600 s? ………………………………………………………………………………………………… ………………………………………………………………………………………………… [2 marks] e. If the rate of heat supplied to the naphthalene is constant at 100 W, and the mass of the naphthalene is 200 g, calculate the specific latent heat of fusion of naphthalene. [3 marks]

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14

Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

3. Diagram 1 shows two weights P and Q, of the same mass but of different materials, placed in a steam bath. On the right are two polystyrene cups containing the same amount of water. Diagram 2 shows the situation after the two weights are transferred into separate cups and thermal equilibrium is reached. thermometer A thermometer B

steam bath steam out
P Q

water polystyrene cup Diagram 1

steam in

thermometer A

thermometer B

steam bath steam out steam in
P

water polystyrene cup
Q

Diagram 2 a) What is meant by thermal equilibrium? [1 mark] b) Bases on Diagram 1 and Diagram 2, compare the temperature of the weights P and Q when they are in the temperature bath and when they are in the polystyrene cups. Relate the change of water temperature in each cup to the amount heat given out by P and Q. Hence determine which weight contains more heat and name the physics concept relating to the amount of heat stored in an object. [5 marks] c) i) When a cannon ball is dropped to the ground from a tall building, its temperature is found to be higher after hitting the ground. Explain why. [1 mark] ii) State the transformations of energy of the cannon ball. [1 mark] iii) What happens to temperature of the cannon ball after some time? Explain.

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15

Physics Module Critical Topic : HEAT Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

[2 marks] d. Diagram 3 shows an electric oven being used to roast a chicken. It is found that the chicken is not evenly cooked and the oven consumes too much electricity. Suggest modifications that can be made to the oven so that the problem stated can be solved. Explain each medication suggested. [10 marks] Heating element

Several types of gas containers are available for the above experiment as shown in the table. Study and explain the suitability of each property of the containers. Choose the most suitable container and give a reason for your choice. Gas container Conduction of heat P Q R S good poor good poor Properties of the material of the container Specific heat Expansion Thickness of wall capacity / J kg-1 oC - when heated
1

PART II: 1. a. 30 oC b. Rate of heat loss increases with temperature difference over the room temperature. At 60oC, the rate of heat loss = rate of heat supplied by the heater. c. rate of change of temperature d. the rate of loss of heat at B is greater than the rate of heat loss at A e. Heat = mc = 1 x 900 x (60 – 30) = 27000 J 2. a. to keep the temperature uniform throughout the water b. 80 oC

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Modul Fizik JUJ Pahang c. i) changing from solid to liquid (melting) ii) During melting, heat supplied is used only to separate/increase distance between the molecules to form liquid. Heat supplied is not used to increase the random kinetic energy of the molecules. d. All the naphthalene has melted and energy supplied increases the kinetic energy of the molecules. e. Heat supplied = 100 x 400 J = 40000 J Heat supplied = mL 40000 = 0.2 L L = 200000 J kg-1. 3. a. No nett heat flow between 2 bodies b. -In the steam bath both P and Q have the same temperature -The temperature of P is lower than Q when they are in the cups -The bigger the change of temperature, the larger the amount of heat given out by the weight -Q contains more heat -The concept of heat capacity- the larger the heat capacity of a body, the more heat is stored in the body at a certain temperature c. i) The kinetic energy of the cannon ball is converted to heat after hitting the ground. ii) Potential energy  kinetic energy  heat iii) same as the surrounding temperature. Thermal equilibrium is reached d.

1

Modification Length and shape of heating element

Reason Covers larger area to spread heat more evenly

2 3 4 5

Have another heating element at the bottom Inner-wall of the oven made of insulating heat resistant material Glass door made double layer with air in between. Add electric motor to rotate the food

Modul Fizik JUJ Pahang 4. Property of material suitable for gas container Reason Good conductor of heat Gas in container absorbs heat quickly Specific heat capacity must be low Temperature of container attains the temperature of surrounding water quickly Little expansion Volume of gas in container kept constant Wall of container must be thin Heat quickly transferred to gas in container Choose container R Because its made of good conductor, low specific heat capacity, expand very little and has thin wall.

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

TOPIC 5 : LIGHT

LIGHT

REFLECTION

TOTAL INTERNAL REFLECTION GLASS BLOCK

REFRACTION

PLANE MIRROR

CURVED MIRROR

REAL DEPTH & APPARENT DEPTH

LENSES

CONCAVE MIRROR

CONVEX MIRROR

CONVEX LENS

CONCAVE LENS

TELESCOPE

MICROSCOPE

MAGNIFYING LENS
5.0 Reflection of light Normal Incident ray
i r

Reflected ray

The laws of reflection: (i) The incident ray, the reflected ray and the normal all lie in the same plane. (ii) The angle of incidence is equal to the angle of reflection. i=r

1

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

5.1 1.

Plane mirror Ray diagram Object Image Step 1 : Draw the image equal distance from the object. Step 2: Draw rays (straight lines) from the image to the eye. Step 3: Complete the rays from the object to the mirror.

Similarities of compound microscope and telescope Consists of two lenses. The first image is real, inverted and acts as the object for the eyepiece. The eyepiece acts as a magnifying lens. The final images are virtual, inverted and magnified.

Note: When determine the refractive index, n the light ray must assume move from air to glass. However, the phenomenon of total internal reflection only occur when the light ray travel from glass to air.

8

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

5.4.1 1.

Applications of total internal reflection Optical fibre

2.

Diamond

9

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

SECTION A:MULTIPLE CHOICE 1 Diagram shows the path of a light beam from air into a glass. Which of the angle is the critical angle?

A

Air

Glass B C

D
2 Diagram shows a ray of light in air entering a semi-circular glass block at an angle of incidence 42 o. Which diagram shows the subsequent path of the ray? A B

42

o

42o

C

D

42 o

42o

3.

Diagram shows a ray, X, is directed into a glass block. The critical angle of the glass is 42 o. Which direction does the light travels from point Y?

Which of the following are the characteristics of the image formed by a plane mirror? A. B C D Inverted, same size and real Upright, same size and real Upright, magnified and laterally inverted Laterally inverted, same size and virtual

20 A convex lens is used as a magnifying glass. What are the characteristics of the image? A magnified, upright, virtual B magnified, upright, real C magnified, inverted, virtual D magnified, inverted, real

SECTION B: STRUCTURED QUESTION Diagram 1 shows a cat’s eye fixed into a road to help drivers when it is dark or foggy.

(a)

What is meant by critical angle? Tick ( √ ) the correct answer in the box provided.

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

The angle of incidence when the angle of refraction is 90o .

The angle of incidence when the incident ray is totally reflected. [1mark] (b) Based on diagram 1 what happen to the light ray after passing point B?
……………………………………………………………………………………

[1mark] (b) Based on diagram 1 how does the cat’s eye help the driver? ……………………………………………………………………………… ……………………………………………………………………………… [2 marks]

2.

Diagram 2.1 and Diagram 2.2 show an identical pencil is immersed in the distilled water and sea water respectively.

Pencil

Distilled water

Sea water

DIAGRAM 2.1

DIAGRAM 2.2

Based on Diagram 2.1 and Diagram 2.2, (a) compare the bending of the pencil …..………………………………………………………………………………………. ..…………………………………………………………………………………………. [1 mark] compare the density of distilled water and the sea water

(b)

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

..…………………………………………………………………………………………. …………………………………………………………………………………………. [1 mark] (c) state the relationship between the density of water with the bending of the pencil ..…………………………………………………………………………………………. [1 mark] (d) Based on Diagram 2.1, compare the size of the observed pencil inside and outside the distilled water …………………………………………………………………………………………………. ………………………………………….………………………………………………………. [1 mark] (e) Name the phenomenon shown in Diagram 2.1 and Diagram 2.2

…………………………………….……………………………………………………………. [1 mark]

3.

Diagram 3.2 shows the formation of the image of an object by a lens X. In Diagram 3.3, another lens, Y, is used to form the image of the same object. Lens X

Object Image

Diagram 3.2 Lens Y

Object Image

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Physics Module Critical Topic : Light Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2010

(a)

(i)

Diagram 3.3 State the light phenomenon that takes place in the endoscope. …………………………………………………………………………………. [1 mark] State two advantages of using a fibre optic cable. ..…………………………………………………………………………………

(ii)

…………………………………………………………………………………. [2 marks] (b) For each case, compare; (i) the size of the object and the size of the image ………………………………………………………………………………. [1 mark] (ii) the object distance and the image distance ....................................................................................................................... [1 mark] Compare the focal length of lens X and lens Y.

SECTION B: STRUCTURED
1(a) The angle of incidence when the angle of refraction is 90o. (b) Reflection/total internal reflection//totally reflect//reflect (c) Reflection of light from the car headlight back to the driver giving an indication of 1 1 2 4

its position.
TOTAL

2 (a) (b) (c) (d) (e)

Pencil in Diagram 6.2 more bending/vice versa Density of seawater is higher/ vice versa The higher the density the greater the bending The size of the pencil in the water is greater Refraction TOTAL

1 1 1 1 1 5

3 (a)(i) (ii)

Total internal reflection - can carry large amount of data/information - transmit signals with very little loss - can transmit large amount of signals at one time - very much thinner and lighter in diagram 2.2 / 2.3 the size of object is equal to the size of image in diagram 2.2 / 2.3 the object distance is equal to the image distance Focal length of lens X is shorter than the focal length of Y Lens X is thicker than lens Y The thicker the lens, the shorter the focal length
TOTAL

Understanding Waves 1. 2. 3. 4. 5. 6. 7. 8. Waves transfer energy without transferring matter. There are two types of waves, transverse and longitudinal waves. The direction of propagation of a wave is perpendicular to its wavefront. The amplitude, A of an oscillation is the maximum displacement from the mean position. The period, T of the oscillation is the time taken to complete one oscillation. The frequency, f of the oscillation is the number of complete oscillations made in one second. The wavelength,  is the horizontal distance between two successive crests or troughs. Wave speed , v v = f

9. Damping is said to have occurred in an oscillating system when the system loses energy to the surroundings, usually in the of heat energy. 10. Resonance in an oscillating system occurs when it is driven at its natural frequency by a periodic force.

6.2

Analysing Reflection of Waves 1. Reflection of waves refers to the return of all or part of the waves when they encounter an obstacle. 2. In the reflection of waves, the angle of reflection is equal to the angle of incidence. 3. The wavelength, frequency and speed of the reflected waves are the same as that of the incident waves.

6.3

Analysing Refraction of Waves 1. Refraction of waves is a phenomenon where there is a change of direction in the propagation of waves when they move from one medium to another due to a change of speed. 2. The frequency of the refracted waves is the same as that of the incident waves.

6.4

Analysing Diffraction of Waves 1. Diffraction is the spreading out of waves when they move through a gap or round an obstacle. 2. The wavelength, frequency and speed of the diffracted waves are the same as that of the incident waves. 3. The amplitude of the incident waves is bigger than the diffracted waves.

6.5

Analysing Interference of Waves 1. The principle of superposition states that when two waves overlap, the resultant displacement is equal to the sum of the displacements of the individual wave. 2. Interference occurs when two wavefronts meet. The waves either interfere constructively or destructively. 3. The approximate formula for interference :  =

Analysing Electromagnetic Waves 1. The electromagnetic spectrum consists of gamma rays, X-rays, ultraviolet rays, visible light, infrared rays, microwaves and radio waves. 2. All electromagnetic waves are transverse in nature and undergo the phenomena of reflection, refraction, diffraction and interference. 3. All electromagnetic waves do not carry any charge and travel through a vacuum with the speed of c = 3.00 x 10 8 m s-1 4. Electromagnetic waves consist of a combination of oscillating electric and magnetic fields perpendicular to each other.

Figure below shows the wavefronts of a incident plane wave. Complete the diagram to show the refracted wavefronts. Your diagram should include the normal, directions of propagation of incident and reflected waves, and labels for angle of incidence, i and angle of reflection, r.

obstacle

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Physics Module Critical Topic Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

4.

Complete the diagram below to show the refracted wave. Your diagram should include the normal, directions of propagation of incident and refracted waves, and labels for angle of incidence, i and angle of refraction, r air

glass

5.

Complete the following diagrams by drawing the wavefronts to show the diffraction of caer waves.

a)

b)

c)

d)

6.

Complete the table by describing the state of motion of each bead and the type of interference that occurs at W, X, Y and Z. Bead W X Y Z State of motion Type of interference

Crest

trough

7.

Figure shows the electromagnetic spectrum. Name A – G

A B

C D

E F

G

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Physics Module Critical Topic Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

8.

An engineer standing at P hears the sound of an explosion at X. After the explosion, he hears two bangs. One bang is heard a fraction of a second after the other. The second bang is an echo from …………..

9.

Which number is i) the incident angle : ……………………………………. ii) the refracted angle : ……………………………………

10.

In a Young double-slit experiment, a student recorded the following data. Distance between the double slits and the screen = 1.5 m Distance between two adjacent bright fringes = 1.8 mm Wavelength of the light waves = 600 nm Calculate the distance of separation between the slits.

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Physics Module Critical Topic Student Module

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Section B : Objectif questions 1. Which of the following statements is true? A B C D 2. Sound waves travel very slowly in vacuum Sound waves travel faster in air than in water Sound waves are transverse waves Sound waves travel faster in solid than in air

The diagram shows the mirages are formed on a hot day. What is the phenomenon involved? A. B. C. D. 5. Reflection Refraction Diffraction Total internal reflection

In the following ray diagram, the image formed on the screen is not clear (not sharp). Lens Object Screen

DIAGRAM Which of the following changes will produce a sharp image on the screen? A. B. C. D. Replace the lens with another convex lens of longer focal length. Replace the lens with another concave lens of shorter focal length. Move the object further from the lens. Move the screen further from the lens.

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Physics Module Critical Topic Student Module

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6.

Diagram shows the graph of displacement against time for a load which is oscillating at the end of a light spring in air. Displacement/cm 10 0 -10 DIAGRAM 1 2 Time/s

Which diagram shows the correct reflection pattern produced when plane water waves are incident on a barrier? A B

C

D

8

Which of the following diagrams show the pattern formed by the wavefronts of water waves passing by an obstacles? A B C

9.

The diagram shows the fringe pattern produced from Young’s double slit experiment using the monochromatic red light source. Bright fringes

Dark fringes What happens to the fringes if monochromatic yellow light source is used? A B C D The bright fringes are wider than the dark fringes The dark fringes are wider than the bright fringes The distance between consecutive fringes decrease The distance between consecutive fringes increase

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Physics Module Critical Topic Student Module

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10.

The diagram shows an ultrasonic waves transmitted from a boat to the seabed to determine the depth, D, of the sea. The speed of the ultrasonic waves in water is 1 500 m s-1. The echo of the waves is received 2.0 s after the transmission.

What is the value of D A B C 375 m 750 m 1 500 m D E 3 000 m 6 000 m

Section C : Structure Question
1.

(a)

Fig. 1.1 shows a machine for making loud sounds. It is called a siren. This consists of a rotating disc with 25 holes. As each hole passes the jet, a puff of air passes through the hole (i) How many puffs of air will there be during one revolution of the disc?

(ii)

The disc rotates 40 times per second. Calculate the frequency of the note produced by the siren.

figure 1.1 (b) The siren described in (a) is located some distance from a large building, as shown in Fig. 1.2.

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Physics Module Critical Topic Student Module

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Figure 1.2 The siren is briefly sounded once. A short time later, the sound is heard again. (i) Why is this second sound heard? ........................................................................................................................ (ii) (iii) 2. What is the frequency of this second sound?……………………………… What is the amplitude of this second sound?………………………………

Boy A throws a large stone into a large still pond, as illustrated in Fig. 2.1.

A

B

(a)

Figure 2.1 Girl B hears the ‘plop’ sound of the stone entering the water a very short time after she sees the splash, but it is many seconds before the water wave reaches the edge of the pond where she is sitting. Use this information to decide which wave travels fastest and which travels slowest. ………………………………………………………………………………………

(b)

Based on answer in a. state each type of wave. ……………………………………………………………………………………..

(c) 3.

State the wave that do not need a substance as the medium to travel.…………….

Fig.3.1 shows three wavefronts in a beam of yellow light passing through air. The wavefronts are one wavelength apart. The beam meets a glass surface. AB is a ray of light that shows the direction of travel of the wavefronts. (a)

Figure 3.1

Complete Fig. 3.1 by (i) continuing the ray AB to show the ray inside the glass, (ii) continuing wavefront 1 inside the glass.

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Physics Module Critical Topic Student Module

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(b)

State what happens to the speed and wavelength of the waves as the beam moves from the air to the glass. (i) speed ..................................................................................................................... (ii) wavelength ......................................................................................................[2]

(c)

The glass in Fig. 3.1 is replaced with a denser glass. Describe two ways in which the completed Fig. 3.1 would change. 1. ................................................................................................................................ ……........................................................................................................................ 2. …............................................................................................................................ ...........................................................................................................................[2]

Section D : 1.

ESSAY

Diagram 1.1 and Diagram 1.2 show the water waves and sound waves propagating towards a reflector.
Incident wavefronts Normal line

Reflected wavefronts

Direction of reflected waves wave DIAGRAM 1.1 Hard surface

Card board tube

i

r

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Physics Module Critical Topic Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

Stop watch

Ear

DIAGRAM 1.2

(a)

(i) (ii)

What is meant by reflected waves?

[ 1 mark ]

(iii)

With reference to Diagram 1.1 and Diagram 1.2, compare the incident and reflected angle, wavelength, frequency, speed and direction of propagation of the reflected wave. [ 5 marks ] State the principle of reflection of waves. [ 1 mark ]

(b)

Discuss on how you would use the sound wave to determine the depth of the sea. [ 3 marks ] You have been assigned as a consultant to assemble a speaker system and to improve the acoustics of a school hall. Using the appropriate physics concept explain how the installation of the speaker system and other modifications that can improve audible sound. In your explanation, elaborate on the following points: (i) The arrangement of the speakers. (ii) Wall and floor finishing. (iii) Power of the loud speakers [10 marks]

Relate λ and x to make a deduction regarding the relationship of both quantities. ( 5 marks ) Two loudspeakers placed 1.5 m apart are connected to an audio signal generator adjusted to a frequency 600 Hz. When a student walks at a distance of 3.0 m infront of the loudspeakaers he hears four consecutive loud and 3 soft sounds Explain why? ( 4 marks ) i) Explain why the wavefronts in the sea follow the shape of the coastline as the water becomes shallower. ( 4 marks ). You plan to build a safe port for the convenience of the fishermen. Suggest relevant steps to be taken in order to build it. ( 6 marks)

Section D : Essay 1. (a) (i) Waves that occurs when it strike the obstacle. (ii) - i = r -  of incident wave =  of refracted waves - f of incident wave = f of refracted waves - v of incident wave = v of refracted waves - Direction of incident wave is change (iii) - transmit the ultrasound with known velocity to the seabed - Take the time taken until the echo detected - Calculate the sea depth, d by using the equation 2d = v x

Student Module

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Physics Answers of Module Critical Topic Exercises

Projek Jawab Untuk Jaya (JUJ) Pahang 2008

(d)

- Two speakers arranged distance to each others - To get nearer position of constructive interference - Two speakers arranged on the straight line in front of hall - Easier to find the louder point (constructive interference) as the audience position - The surface of wall made by soft materials such as carpet or foam. - To reduce the effect of reflection - Use the parquet as the floor - To reduce the effect of reflection - Use powerful loud speaker - To get a good effect of sound and reduce the rate of energy lost.

2.

a) i) Two waves that have same phase or same different phase // same frequency and amplitude. ii) - a for both diagram 2.1 and 2.2 are same - D for both diagram 2.1 and 2.2 are same -  diagram 2.1 greater - x diagram 2.1 greater - the grater the  the grater the x 1. There are two coherent sources placed far to each others, then produced the good effect of interference. 2. The student walks far from the sources, to hear the effect of constructive interference and destructive interference. 3. The student hears 4 time of constructive interference as the louder sound. 4. Soft sounds are the destructive interference occurs in between the constructive interference. i) The phenomenon of refraction occurs when the water becomes shallower. There are some normal line produced, depend on the shape of coastline. The refracted angle produce based on normal line and the change of the depth of water. The direction of propagation will change based on how it refract due to the shape of coastline. Build slanting barrier to reduce speed of wave Build the rough barrier to reduce reflection of the waves Build the new jetty at the bay because the water is calm at the bay Build the small opening surround the bay because diffraction happens at the opening Build the barrier at the bay because the wave is spread according to the shape of the bay

3. Measure by ammeter in series circuit. 4. Activity :(i) To investigate the relationship between electric charges and electric current.

Procedure Bring finger close to the dome of the generator.

Observation Feel a brief electric shock

(ii) To study the electric field around metal electrodes

_ +

Procedure: Two plane electrodes connected to the terminals of an EHT power supply are dipped into a dish of castor oil.

Observation

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Physics Module Critical Topic Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

and some semolina grains is sprinkled on the surface (iii) Ping pong ball

X

Y

Procedure

Observation 1. When switched on, plate X is positively charged and plate Y is negatively charged. 2. When the ping-pong ball touches the positively charged plate X, the ball receives positive charges , then pushed to negatively charged plate Y. 3. When the ball touches plate Y, the positive charges are neutral by the negative charges. The ball then negatively charged and repels toward plate X. The process is repeated and the ball oscillate to and fro between the two metal plates X and Y.

Switch on the EHT power supply and charge the pingpong ball by contact with one of the electrodes

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Physics Module Critical Topic Student Module

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(iv) Candle flame

Procedure To investigate the effect of an Electric field on a Candle Flame

Observation

The bigger portion of the flame is attracted towards the negative plate as the mass of the positive ions is larger than of the negative ions.

3. It can be measured using a voltmeter. Voltmeters must always be connected in parallel between the points concerned.

4. The greater the potential difference or voltage, the greater the current flow.

Ohm’s Law
1. The electric current, I flowing through a conductor is directly proportional to the potential difference across it if the temperature are constant. From Ohm’s Law, VI

2. The resistance (R) of a conductor is defined as the ratio of the potential difference (V) across the conductor to the current (I) flowing through it. R = V I
-1

V I = ohm, Ω R

unit = VA

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Physics Module Critical Topic Student Module

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4. Disadvantage of resistance Resistance causes some of the electrical energy to turn into heat , so some electrical energy is lost along the way if we are trying to transmit electricity from one place to another through conductor. 5. Advantage of resistance It is resistance that allows us to use electricity for heat and light. In a light bulb, the current flowing through a resistance filament causes it to become hot and then glow. 6. The factors that effect the resistance, R (i) length [R is directly proportional to its length, l ]

SERIES AND PARALLEL CIRCUITS
Series Circuit 1. In a series circuit, two or more resistors are connected one end after another to form a single path for current flow. 2. 3. The bulbs share the potential difference from the battery, so each glows dimly. If one bulb is removed, the other goes out because the circuit is broken.

Parallel circuits 1. All the components are connected with their corresponding ends joined together to form separate and parallel paths for current flow. 2. Each bulb gets the full potential difference from the battery because each is connected directly to it. So each bulb glows brightly. 3. The brightness of each bulb in a parallel circuit is brighter than those in a series circuit with the same number of bulbs. 4. If one bulb is removed, the other keeps working because it is still part of an unbroken circuit.

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Physics Module Critical Topic Student Module

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

ELECTROMOTIVE FORCE AND INTERNAL RESISTANCE 1. The electromotive force, E (e.m.f.) is defined as the work done by a source in driving one coulomb of charge around a complete circuit.
-1

Unit of e.m.f. is the volt, V = J C 2. The voltage label on a battery or cell indicates its e.m.f . (i) The label 1.5 V on a dry cell indicates the e.m.f. of the cell is 1.5 V. (ii) A cell has an e.m.f. of 1.5 V if a flow of 1 C of charge produces 1.5 J of electrical energy to the whole circuit. 3. Compare e.m.f. and potential difference 1.5V

• Closed circuit (switch on) • Current flows through the circuit • The reading of the voltmeter will drop a little if a bulb is connected in series to the cell. switch • This drop in potential difference across the cell is caused by the internal resistance of the cell. • If the voltmeter reading is 1.2 V, then the potential difference across the lamp = 1.2 V.

E = IR + Ir ELECTRICAL ENERGY AND POWER 1. Electrical energy is defined as the ability of the electric current to do work. 2. It is supplied by a source of electricity such as cell or battery when current flows in a closed circuit. 3. It can be converted by an electrical appliance into other forms of energy such as heat, light, mechanical when current flows in it. 4. The potential difference, V across two points is defined as the energy, E dissipated or transferred by 1 C of charge, Q that moves through the two points. V=E Q (i) (ii) (iii) E = VQ E = VIt E = IR(It) E = I2Rt E = V2 t R [ From V=IR]

(iv)

[The unit of electrical energy is Joule, J ]

5. Power is the rate of electrical energy dissipated or transferred.
-1

An electrical kettle which is marked 240 V 1500 W means that the electric kettle will consume 1500 J of electrical energy every 1 second if it is connected to the 240 V. The amount of electrical energy consumed in a given time: Energy consumed = Power rating x time E= Pt

7.

8.

The larger the power rating in the electrical appliance, the higher energy is used for every second. The longer the usage time, the higher electrical energy is consumed.

11. Efficiency is a percentage of the output power to the input power. Efficiency = Energy output x 100% = Output power x 100% Energy input Input power The efficiency of an electrical appliance is always less than 100% as some energy is lost in the form of heat and sound. 12. Several ways to increase energy efficiency includes: (i) Use more energy efficient lightings • Replace regular incandescent (filament) light bulbs with compact fluorescent light bulbs. (ii) Proper utilization of all electrical appliances • Run your washing machine only when it is fully loaded & Iron your clothes only when you have at least a few pieces to iron. • Regular cleaning of air filters in air-condition units and clothes dryers. • Defrost refrigerators regularly

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Physics Module Critical Topic Student Module

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13. A fuse is a short piece of thin wire which overheats and melts if current of more than a certain value flows through it. If a short circuit develops in the appliance, a current which is too high will flow. The fuse will melt and prevents overheating of the wire that can cause a fire. 14. Three-pin plug • Live wire, L (brown). A current flows through the circuit • Neutral wire, N (blue). It is a zero potential difference. • Earth wire, E (green)

15. Safety wire which connects the metal body of the appliance to earth. If a live wire touches the metal body of appliance, a large current would immediately flow to the earth and breaks the fuse. This will prevent a person from electrocution.

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Physics Module Critical Topic

Projek Jawab Untuk Jaya (JUJ) Pahang 2009

TOPIC 8 : ELECTROMAGNETISM

ELECTROMAGNETISM
8.1 Analysing the Magnetos Effect of a Current-carrying Conductor 1. 2. An electromagnet is made by winding a coil of insulated wire round a sofá iron core where is becomes magnetised when a current flows. The pattern of the magnetic field due to a current depend on the shape of conductor while the direction of the magnetos field depends on the direction of the current. Right-hand Grip Rule Direction of megnetic field

+ Current direction 8.2 Understanding the Force on a Current-carrying Conductor in a Magnetic Field 1. 2. A magnetic force is exerted on a current-carrying conductor in a magnetic field. The direction of magnetic force can be determined by Fleming’s left-hand rule.
Thumb ( Thrust force )

Intergrated field

Force

First Finger ( Field ) S

N

S

Centre Finger ( Current ) Fleming’s left-hand rule.

The magnitude of the magnetic force on a current-carrying conductor depend on the size of the current and the strength of the magnetic field. 4. A current-carying coil in a magnetic field will experience a turning effect due to the action of a pair of magnetic forces. 5. The magnitude of the turning effect depends on the size of the current, the number of turn of the coil. Student Module 1

Analysing Electromagnetic Induction. 1. 2. 3. An electromotive force is induced in a conductor when there is a relative motion that causes the conductor to cut the magnetic field lines. Faraday’s law status that the magnitude of the induced current is directly proportional to the rate of change or the rate of cutting of the magnetic flux. Lenz’s law status that the direction of the induced current is such that the change producing it will be opposed. N

S

4. 5. 6. 7.

The direction of the induced current can be determined by Fleming’s righ-hand rules. There are two types of generator, the direct current generator and the alternating current generator. A direct current flows in one direction only. The direction and magnitude of an alternating current changes with time.

A step-up transformer supplies an output voltage that is higher than the input voltage. A step-down transformer supplies an output voltage that is lower than the input voltage.

8.5

Understanding the generation and tranmission of ekectricity. 1. 2. 3. 4. 5. Elctricity can be generated from various sources of energy Duch as fósil fuel, nuclear, hydro, wind and solar. Electricity is transmitted through the National Grid Network system. Electricity is transmitted at very high voltage to reduce energy loss. Renewable energy sources such as biomasas, hydro, wind and solar are replaceable. Non-renewable energy sources such as oil, diesel, natural gas and coal are not replaceable.

Notes : Definition of thermionic emission The release of electrons from a heated metal cathode

Vacuum tube

Filament / cathode

Anode

 When the filament is heated, electrons gain sufficient kinetic energy and are released from the surface of the filament  The electrons are emitted and accelerated towards the anode by high potential difference between the anode and cathode Factors influence rate of thermionic emission

Factor Temperature of the cathode Surface area of the cathode Potential difference between the anode and cathode.

Effect on the rate of thermionic emission .When the temperature of cathode increase, the rate of thermionic emission increase Larger surface area of cathode, rate of thermionic emission increase larger surface area of the cathode increases the The rate of thermionic emission is unchanged, when the potential difference increases, but the emitted electrons accelerate faster towards the anode The rate emission is unchanged, when the potential r towards the a

Cathode ray

Properties of cathode ray :  They are negatively charged particles  They travel in straight lines  They possess momentum and kinetic energy  They are deflected by magnetic and electric field

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Cathode ray oscilloscope

Main part

Component Filament

Function When a current passes through the filament, the filament becomes hot and heats up the cathode. Emits electrons when it is hot

 Control the number of electrons hitting the fluorescent screen.  Control the brightness of the spot on the screen To focus the electrons onto the screen
To accelerate the electrons to high speed To deflect the electron beam vertically To deflect the electron beam horizontally To convert the kinetic energy of the electrons to heat and light energy when the electrons hit the screen.

Vp 2 Short time intervals, t = no. of divisions between two pulses × time-base value. a group of materials that can conduct better than insulators but not as good as metal conductors
Effective voltage or root-mean-square voltage, Vr.m.s = Doping is a process of adding a certain amount of other substances called dopants such as Antimony and Boron to a semiconductor, to increase its conductivity

1

n-type semiconductor

 Semiconductor like Silicon doped with pentavalent atoms increase the number of free electron  The silicon will has negative electron as majority charge-carriers and it thus known as an n-type semiconductor. p-type semiconductor

 Semiconductor like Silicon doped with trivalent atoms such as has more positive holes  One of the covalent bonds has a missing electron called a ‘positive hole’  The majority charge-carriers in this semiconductor are the positive holes thus known as a p-type semiconductor.

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Function of semiconductor diode Rectification

allow current to flow through it in one direction only. Rectification is a process to convert an alternating current into a direct current by using a diode

 A resistor, R x and a variable resistor, RY are being used to form a potential divider  If the variable resistor is set to zero, the base voltage is zero and the transistor switches off  If the resistance of the variable resistor is increased, the base voltage will Increases  When the base voltage reached a certain minimum value, the base current, IB switches on the transistor. A large collector current, IC flows to light up the bulb. Definition of a logic gate AND gate
A Y B

Diagram 31.2 shows the change of current, I with time, t for the current which is flowing through R1 in Diagram 31.1 . Which of the following is most suitable to represent the current which flows through R2? Rajah 31.2 menunjukkan perubahan arus, I dengan masa, t bagi arus yang sedang mengalir melalui R1 dalam Rajah 31.1 . Antara berikut, yang manakah paling sesuai untuk mewakili arus melalui R2 ?

Total The resistance in diagram 6.2 is larger than in diagram 6.1 The potential difference in diagram 6.2 is larger than in diagram 6.1 When the resistance increases, the potential difference increases Light dependent resistance Automatic switch / Current amplifier Ratio potential difference to current Logic gates are electronic switches with one or more inputs and one output
Detector 1
Pengesan 1

Notes
Atom Has nucleus consists of proton and neutron with electron move in orbit around the nucleus - X is a chemical symbol of the element - A is a nucleon number - total number of protons and neutrons in a nucleus - Z is a proton number - number of protons in a nucleus / equal to number of electrons atoms with the same proton number but different nucleon number - same chemical properties - different physical quantities - different mass the spontaneous and random disintegration of an unstable nucleus into a more stable nucleus with the random emission of energetic particles or photons - Alpha particles - Beta Particles - Gamma rays - Positively charged - strongest ionizing power and low penetrating power - can be stopped by a thin sheet of paper - deflected by electric and magnetic field - negatively charged - moderate ionizing power and moderate penetrating power - can be stopped by a few millimeters of aluminium - deflected by electric and magnetic field - Neutral charge - weakest ionizing power and highest penetrating power - can be stopped by A few centimeters of lead or concrete -not deflected by electric and magnetic field

Explain the suitability of the characteristics of the radioisotope to be used in the controlling the population of pests based on the following aspects: Terangkan kesesuian ciri-ciri radioisotope untuk digunakan dalam mengawal populasi serangga berdasarkan aspek-aspek berikut: State of matter Keadaan jirim Types of ray Jenis sinar Half-life Separuh hayat

An alpha particles is positively charged Unstable isotopes which decay and give out radioactive emissions Electron G-M tube not strong enough to pass through the juice will not stop by the juice Lead container E the most radioactive emission pass through the juice there is still show a reading because of the back ground reading A process where an unstable nucleus becomes stable with the emitting of radioactive ray - Curve shape is the same / exponential - The activity reduces with time - The activity reduces faster in Diagram 10.2 - The time for the activity to become half of the original activity is more for diagram 10.2 - Half-life T1/2 - The power of ionisation is high - so it will effect the human body - The power of penetration is low

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so that it cannot be detected by detector - The power of penetration is high - The power of ionisation is low use MRI / X- - Identify the position of cancer cells ray conectly point out to the - To avoid other living cells from target being destroyed accurately Suitable dose - If high dose, other cells will destroy - If low dose not all the cancer cells will be destroyed Time of To prevent other healthy cells from exposure is not destroy too long Gamma